Polyurethane Foam In Foundation Footings For Load-Bearing Structures

Abstract

Foundation footing system for a load-bearing structure comprising a hole in the ground and a post in the hole extending above the hole. A gap present between the sides of the post and the sides of the hole contains a cured, hydrophobic, closed-cell, polyurethane foam to firmly hold the post in place and protect the post from moisture. Alternatively, a foundation footing system for a load-bearing structure comprising a hole in the ground filled with a cured, hydrophobic, closed-cell, polyurethane foam and a post place on and connected to the top of the foam.

1 . A foundation footing system for a load-bearing structure comprising a hole in a ground, the hole having a bottom and sides, and a post positioned in the hole and generally centered within the hole, wherein the post extends above the hole, wherein the width of the hole is wider than a width of the post thus forming a gap between sides of the post and the sides of the hole; the foundation further comprising a cured, closed-cell, polyurethane foam surrounding the post and in direct contact with the sides of the hole, wherein the polyurethane foam fills the gap between the post and sides of the hole, the polyurethane foam comprising a cured mixture of a polyurethane composition comprising polyisocyanate and at least one active hydrogen containing compound wherein the cured polyurethane foam has a compressive strength of greater than about 80 psi. 
     
     
         2 . The foundation footing system of  claim 1  comprising at least two holes and at least two posts, wherein the posts have the same or different diameters, and each hole has a diameter accommodating the diameter of the respective post and requisite gap, wherein a load bearing structure resides on the at least two posts. 
     
     
         3 . The foundation footing system of  claim 1  wherein the cured polyurethane foam is prepared from mixing a polyurethane composition, pouring the composition into the hole, and allowing the composition to foam, wherein the polyurethane foam cures to touch in about 1 to 10 minutes after mixing the composition. 
     
     
         4 . (canceled) 
     
     
         5 . The foundation footing system of  claim 1  wherein the cured polyurethane foam has a compressive strength of 100 psi. 
     
     
         6 . The foundation footing system of  claim 1  further comprising a footing pad underneath the post positioned in the hole. 
     
     
         7 . The foundation footing system of  claim 1  wherein the polyurethane composition is hydrophobic. 
     
     
         8 . The foundation footing system of  claim 1  wherein the polyurethane foam further comprises at least one water-immiscible component in an amount from 10% to 80% by weight of the total composition. 
     
     
         9 . The foundation footing system of  claim 8  wherein the water-immiscible component(s) comprises 30% to 60% by weight of the total composition. 
     
     
         10 . The foundation footing system of  claim 1  wherein the composition further comprises a hydrophobicity inducing surfactant in an amount from 0.1% to 5% by weight of the total composition. 
     
     
         11 . The foundation footing system of  claim 10  wherein the surfactant is selected from polysiloxane-polyalkylene oxide copolymers. 
     
     
         12 . The foundation footing system of  claim 1  wherein the post is positioned at the bottom of the hole. 
     
     
         13 . A foundation footing system for a load-bearing structure comprising a hole in a ground, the hole having a top, bottom, and sides; the foundation further comprising cured, polyurethane foam, wherein the foam fills the hole and extends above the top of the hole to form a foundation footing, the polyurethane foam comprising a cured mixture of a polyurethane composition comprising isocyanate, and at least one active hydrogen containing compound; and further comprising a post placed on and attached to the top of the foam and generally centered on the foam, wherein the cured polyurethane foam has a compressive strength of greater than 10 psi. 
     
     
         14 . The foundation footing system of  claim 13  comprising at least two holes and at least two posts, wherein the posts have the same or different diameters, and each hole has a diameter accommodating the diameter of the respective post and requisite gap. 
     
     
         15 . The foundation footing system of  claim 13  wherein the cured polyurethane foam is prepared from mixing a polyurethane composition, pouring the composition into the hole, and allowing the composition to foam, wherein the polyurethane foam cures to touch in about 1 to 10 minutes after mixing the composition. 
     
     
         16 . The foundation footing system of  claim 13  wherein the cured polyurethane foam has a compressive strength of greater than 30 psi. 
     
     
         17 . The foundation footing system of  claim 13  wherein the cured polyurethane foam has a compressive strength of greater than 50 psi. 
     
     
         18 . The foundation footing system of  claim 13  wherein the polyurethane composition is hydrophobic. 
     
     
         19 . The foundation footing system of  claim 13  wherein the polyurethane foam further comprises at least one water-immiscible component in an amount from 10% to 80% by weight of the total composition. 
     
     
         20 . The foundation footing system of  claim 19  wherein the water-immiscible component(s) comprises 30% to 60% by weight of the total composition. 
     
     
         21 . The foundation footing system of  claim 13  wherein the composition further comprises a hydrophobicity inducing surfactant in an amount from 0.1% to 5% by weight of the total composition. 
     
     
         22 . The foundation footing system of  claim 21  wherein the surfactant is selected from polysiloxane-polyalkylene oxide copolymers. 
     
     
         23 . The foundation system of  claim 1  wherein the sides of the hole are scarified to increase the friction between the soil and the footing.